Budget forecast

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description clearly states 'without creating anything', aligning with the readOnlyHint and destructiveHint annotations. It additionally discloses a non-obvious behavior: per-keyword max_cpc values are collapsed to a campaign-level cap, which is valuable transparency beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description leads with the purpose, then a caveat, then parameter details, which is logical and mostly concise. Some redundancy exists (max_cpc appears both in the keyword object and as a standalone note), but it does not significantly harm readability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given an output schema exists, the description adequately explains what the tool does and the key inputs. It lacks an explicit mention of the output shape or any error/rate-limit behavior, and customer_id is unexplained, but these are minor gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Prose descriptions cover keywords, max_cpc, geo_target_id, language_id, daily_budget, and forecast_days with defaults and example values, compensating for the schema's lack of descriptions. However, customer_id is not explained at all, leaving one parameter semantically undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('Forecast') and precise objects ('clicks, cost, and conversions for a set of keywords'), clearly distinguishing this from reporting or discovery tools. Mentioning Google Ads Keyword Planner adds concrete context without ambiguity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly identifies the use case ('Essential for budget planning before launching campaigns') and notes the operation creates nothing, indicating when it is safe to use. It does not explicitly contrast with alternative tools, but the context is sufficient for most agents.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.